余倍体小滨麦与普通小麦杂交后代的细胞遗传学研究

本文对八倍体小滨麦与普通小麦杂交后代的细胞遗传学及附加染色体的传递及丢失规律进行了研究和讨论。结果表明,ＢＣ１Ｆ１与Ｆ２相比较,染色体分离范围小,并且分离向染色体数目减少偏移,有利于４３、４４条染色体的分离;双单体附加和单体附加后代异染色体丢失严重,分别为６５．７９％和６１．９９％,双单体附加分离出单体附加占１０．５３％,单体附加的传递率为２６．９２％,单体附加后代分离出的二体附加为５．５６％,二     

八倍体小滨麦与缺体小麦杂交的细胞遗传学研究

八倍体小滨麦与缺体小麦杂交和回交,其后代ＢＣ１Ｆ１与Ｆ２相比较,染色体分离范围小,有利于４１条染色体类型的分离,若用异源双单体附加作父本与缺体回交,４１条染色体类型的分离率还会提高２倍左右;单体代换在自交世代的传递率为３１．９１％,二体代换的分离率为１９．３７％,异染色体的丢失率为２９．３４％;二体代换在自交世代的传递率为８５．２６％,异染色体的丢失率为９．２１％;ＰＭＣＭＩ染色体构型为２０．７６”＋０．３１’＋０．０３＂＋０．０１””,相对紊乱系数为０．０１,２ｎ＝２１”的细胞占８６．０９％。选育的二体代换系,不同程度地表现出大穗、多花、优质、抗多种病害等滨麦的优良性状。     

八倍体小滨麦与4D缺体杂交后代小染色体的传递与遗传效应

７２１８０ ４Ｄ缺体附加的１对小染色体（ｔｉ）为亚中部着丝点染色体,其大小为常染色体平均长度的１／３￣１／４。ＰＭＣ ＭＩ,染色体构型为１９．５９”（１８￣２０）＋０．４６’（０￣４）＋０．０９””（０￣１）＋０．９６ｔｉ”（０￣１）＋０．０８ｔｉ’（０￣２）,９６．１９％的细胞中,ｔｉ 色体联会成环状二价体,８２．３８％的ｔｉ”游离在赤道板两边,与常染色体不联会,且推后分离,与八倍体小滨麦杂交的     

普通小麦×大麦杂种后代细胞遗传学研究

普通小麦×大麦杂种与普通小麦回交,产生了具有普通小麦细胞质带有部分大麦细胞核的普通小麦－大麦属间杂种后代,对其连续多年套袋自交,测交、细胞学鉴定和定向选择,从自交后代群体中筛选出一部分异附加系、异代换系和易位系街人有大麦某些特性的小析类型,并系统地对本和二体附加系自交后代染色体的分离行为作了遗传分析。结果表明：２ｎ＝４３的单体附加标株自交分离出单体附加的频率为２５．６％,二体附加的频率为１．２％;     

普通小麦与东方旱麦草异附加系和异代换系的选育与原位杂交检测

旱麦草属（Ｅｒｅｍｏｐｙｒｕｍ）是用于小麦品种改良的又－潜在的植物资源。为了筛选小麦－旱麦草异附加系、异代换系,对普通小麦品种 Ｆｕｋｏｈｏ×东方旱麦草属间杂种的 ＢＣ２Ｆ３代材料的９６粒种子进行了染色体数目的检测,共检出１５粒２ｎ＝４３的种子, ８粒 ２ｎ＝ ４４的种子,进一步对以上材料进行的基因组ＤＮＡ原位杂交,共鉴定出３个单体附加系,２个二体附加系,１个双单体附加,１个小麦三体单体附加,１个附加３条东方旱麦草染色体的小麦单体,在染色体数为４２的个体中,检测出１个单体代换,１个双单体代换。根据ＢＣ２Ｆ３代自交品系来源的不同,初步认为由双单体附加自交比单体附加自交选择异附加系的效率高。     

将大赖草种质转移给普通小麦的研究──Ⅲ．抗赤霉病异附加系选育

大赖草比抗病品种“苏麦３号”更抗小麦赤霉病。经离体和活体赤霉病抗性单花滴注鉴定和有丝分裂中期及减数分裂中期Ⅰ的Ｃ－分带分析,选育出添加了１对第２染色体的抗赤霉病异附加系,其４４条染色体在ＭＩ配成０．１２—０．４０ⅠＩ＋２１．７０—２１．９３Ⅱ＋０．０１—０．０４Ⅳ。经Ｃ－分带和生物素标记的染色体组ＤＮＡ作探针的分子原位杂交分析证实添加的１对外源染色体在ＭＩ配成二价体,在细胞学上已基本稳定。     

将大赖草种质转移给普通小麦的研究：VI.端体异附加系的选育与鉴定

利用根尖细胞有丝分裂中期染色体计数,花粉母细胞减数分裂中期１（ＰＭＣ ＭＩ）染色体构型分析仪及Ｃ－分带,从普通小麦中国春与大赖草（ＬｅｙｍｕｓｒａｃｅｍｏｓｕｓＬａｍ．）杂种回交后代中,选育出两个端二体异附加系９５Ｇ０９,９５Ｇ１１和一个添加了一对大赖草第１４号染色体和另一对端体的双重异附加系９５Ｇ３０２（２ｎ＝４４＋２ｔ）,它们的ＰＭＣ ＭＩ染色体配对构型分别为０．２１个单价体（其中０．１６个端     

将大赖划种质转移给普通小麦的研究

大赖草比抗病品种“苏麦３号”更抗小麦赤霉病。经离体和活体赤霉病抗生单花滴注鉴定和有丝分裂中期及减数分裂中期Ｉ的Ｃ－分带分析,选育出添加了１对第２染色体的抗赤霉病异附加系,其４４条染色体在ＭＩ配成０．１２－０．４０１＋２１．７０－２１．９３Ⅱ＋０．０１－０．０４Ⅳ。经Ｃ－分带和生物素记的染色体组ＤＮＡ作探针的分子原位杂交分析证实分析证实添加的１对我源染色全在ＭＩ配成二价体,在细胞学上已基本稳定。     

甘蓝型油菜与蓝花子远缘杂交及双二倍体的合成研究

甘蓝型油菜品种奥罗×蓝花子杂种Ｆ-１,平均配对构型为１２．１Ⅰ＋６．５３Ⅱ＋０．４１Ⅲ＋０．１８Ⅳ＋０．１８Ⅴ,Ａ、Ｃ染色体组与Ｒ染色体间存在配对,它们之间具有一定的同源性。在甘蓝型油菜与蓝花子的杂种Ｆ-１代中,存在一种染色体不配对的减数分裂类型。这一类型中有少量可形成平衡的不减数配子。提供了油菜与蓝花子远缘杂种回交结实的细胞学根据。在ＭＳ＋０．２ｍｇ／ＬＮＡＡ＋３ｍｇ／ＬＢＡ＋１ｇ／Ｌ秋水仙碱＋３０ｇ／Ｌ蔗糖＋８ｇ／Ｌ琼脂的培养基中,接种甘蓝型油菜奥罗与蓝花子的杂种Ｆ-１进行加倍处理,经快速繁殖后,获得大量的染色体数为２ｎ＝５６的双二倍体幼苗。上述双二倍体自交结实,在减数分裂中绝大多数细胞形成２８个二价体,个别形成２６个二价体和１个四价体。上述技术在油菜与蓝花子远缘杂交中首次解决了用常规方法不易获取远种杂种稳定双二倍体的难题。甘蓝型油菜品种Ａｌｔｅｘ×蓝花子杂种Ｆ-１代,长时间的快速繁殖后,出现了染色体丢失和加倍,有形成１９条染色体的配子回复到甘蓝型油菜染色体组成的趋势。在油菜远缘杂种中发现了类似于球茎大麦远缘杂种中染色体丢失的现象。     

将大赖草种转移给普通小麦的研究Ⅵ.端体异附加系的选育与鉴定

利用根尖细胞有丝分裂中期染色体计数、花粉母细胞减数分裂中期Ｉ（ＰＭＣＭＩ）染色体构型分析以及Ｃ－分带,从普通小麦中国春与大赖草（ＬｅｙｍｕｓｒａｃｅｍｏｓｕｓＬａｍ．）杂种回交后代中,选育出两个端二体异附加系９５Ｇ０９．９５Ｇ１１和一个添加了一时大赖草第１４号染色体和另一对端体的双重异附加系９５Ｇ３０２（２ｎ＝４４＋２ｔ）,它们的ＰＭＣＭＩ染色体配对构型分别为０．２１个单价体（其中０．１６个端体单价体）、１９．５７个环状二价体＋２．３２个棒状二价体（其中０．９２个由两端体配对构成）,１．５２个单价体（１．４４个端体单价体）＋１８．０７个环状二价体＋３．１７个棒状二价体（０．２８个由两端体配对构成）,１．０３个单价体（０．７２个端体单价体）＋１８．８９个环状二价体＋３．６１个棒状二价体（０．６４个由两端体配对构成）。运用单花滴注技术对这些材料在活体和离体条件下进行赤霉病人工接种鉴定,结果表明：９５Ｇ３０２的抗性与抗赤霉病对照品种苏麦３号相仿;９５Ｇ１１的抗性高于苏麦３号,明显高于亲本品种中国春。还对端体附加系的利用以及有效、快捷地转移赤霉病抗性基因进行了讨论。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.